Closure cap for glass containers



Nov. 12, 1963 G. F. CHAPLIN 3,110,409

CLOSURE CAP FOR GLASS CONTAINERS Filed ocr. 2e, 1961 2 sneek-sheet 1 rENTOR.

Nov. 12, 1963 G. F. cHAPLlN cLosuRE CAP FOR GLASS CONTAINERS 2Sheets-Sheet 2 Filed OCT.. 26, 1961 The present 'invention is primarilyconcerned with the particular conformation of the cap shell in theregion ol the `corner -orrned in pant by the top panel portion "i and inpart by the depending skirt portion 3 together with the specialconformation of the gasket lil lodged in place therein. Reference is nowmade to FIGS. 6 and 7 for a detailed description Iof these features ofthe closure cap t3. Adjacent Athe outer periphery of the top panelportion 7 and forming the outer margin thereof, the cap shell has adown-turned chan-nel portion indicated generally at l5 in FIGS. 6 and 7with the inner wall thereof being indicated at 16, the outer wallportion being indicated at 3.7, and with the flat interconnectingportion of the channel being indicated at l. The outer wall portion 17integrally merges with a downwardly, and outwardly tapered skirt portion2.6* which at its lower end merges with a reversely 'curved portion ofthe skirt 2l. The skirt portion 21 which connects with the lower end ofthe skirt portion Ztl is both outwardly and downwardly ilared and themiddle of this double-curved portion 2l constitutes a shoulderintermediate the inner step portion 2% or the skirt and the outer,substantially straight or vertical, portion 22 thereof which carries thebead 1l and lugs l2.

The gasket lll includes a main cushion portion 23 which completely tillsthe downward channel l5, and a downwardly and outwardly taperedelongated portion L4 which follows `down along the inside of the taperedportion 20 of the cap shell. terminates in an outwardly ilared featheredge portion 25 which actually ends at approximately 26 underneath theshoulder portion of the shell. it will be seen that the upper edge ofthe gasket lli terminates on the underside yof the top panel portion 7adjacent the bottom end of the channel forming wall i6, as indicated at27.

The gasket ltlmay be formed of various known rubber-like resilientgasket materials having the desired physical and chemical properties. Apreferred class of materials from which the gaskets lo may be formed arethe resin compositions known in the art as plastisols A preferredplastisol type gasket composition is described in detail in Unger :andZipper Patent No. 2,874,863. The gaskets itl may be deposited in the capshells by various known techniques, one being the so-called ilowed-intechnique wherein the plastisol composition is uncured, paste-likecondition is squirted' from one or more nozzles into the cap shells (atposition 8 cap shell portion FIG. 5) whichare turned upside down on achuck rotating at high speed. Due to centrifugal force the gasketmaterial will assume the desired contour und shape. After being thusdeposited or flowed-in the gaskets are cured or set by a heatingoperation according to known procedures and using known equipment. rThecured gaskets will permanently adhere to the interior `of the shell.

According to another technique the proper amount of gasket material canbe deposited in the corner portion and then it can be correctly shapedby a forming die which may also be heated `so as to simultaneously shapeand cure the gasket material.

The present invention is not particularly concerned with either thedetails of the gasket composition or the particular technique used informing it into the gaskets 1t?. Rather, any suitable rubber-likeresilient gasket material having the proper physical and chemicalproperties may lbe used, and any suitable manufacturing techniques maybe employed.

The sealing finish of the glass jar 5 comprises a top edge portion 3Gwhich merges with a :beveled ortapered side seal portion 3l. Therelative relationship of the gasket lil, and the glass finish when theclosure cap 6 is in'fully sealed position are shown .in FIG. 7. Theclosure caps d are applied to the iilled glass jars S and turned Y downto fully sealed position thereon in known manner using lnown high speedcapping equipment. Generally, this 4combined capping and sealingoperation begins with applying the caps loosely onto the mouths of thejars At its lower end, the gasket lo f CIT passing through an atmosphereof steam, and then turning the caps down lightly to position with thelugs 12 engaging underneath the glass lugs l. Then while the jars rerestrained from turning, the caps 6 are turned down to their ifull `downand sealing position bringing about the relationship of the gasket andsealing iinish shown in HG. 7. The head space in each of the jars isiilled with `steam during the capping operation so that when thistrapped steam condenses after capping, a vacuum is created within thehead space which enhances the hermetic seal between the gasket l@ andthe glass finish.

Referring to FlG. 7 it will be seen that the top edge of the sealingnish of the glass container has upwardly compressed the gasket materialin the cushion area 23 with the result that an inner part of lthe gasketmaterial is bulged inwardly as indicated at 32 in FlG. 7. However, thebulged portion 32 is under compression so that there is no tendency tolift or loosen the seal formed between the `gasket and the interior ofthe shell in the vicinity of the lower end of the chan-nel wall lo wherethe gasket edge terminates at 27. At the same time the tapered pontion2li of the gasket is upwardly ironed or drawn out so as to completelyblanket the inclined side sealing area 3l of the glass finish and extenddownwardly there beyond to the vertical portion of the glass eX- teriorindicated at 33. lt will be seen that the gasket material is :materiallythinned out where it is caught between the `glass iinish 3l a-nd theopposing skirt portion area Zt of the cap shell. As a matter of fact thecap shell in this area is placed under hoop tension as a result ofsealing. This condition is indicated in FlG. 7 wherein the originalcontour of the unapplied cap shell is shown in broken lines while thedistended applied condition is shown in fall lines as indicated at 35.rThis hoop tension in the shell places the adjacent gasket materialunder compression and brings about a very high degree of sealing actionin this region.

As indicated above, there are three main sealing areas provided by thegasket lil in combination with the cap shell and the sealing nish on therim of the container. The rst seal is formed at the feather edge 26.Since this seal is located at a relatively remote distance from theportions of le gasket which are engaged with the glass iinish, andbecause of the thinness of the feather edge portion and the inabilitythereof to transmit compression forces, this feather edge seal at Z6 isfully protected and easily maintained so that no part of the atmospherehas an opportiunity to gain entrance between the gasket l@ and the capshell portion S.

The second portion of the seal is in the area where the thinned out,tapered skirt portion 24 of the gasket is maintained under radialcompression between the distended portion 35 ol the cap shell and theunyielding opposing tapered nish 3l. The leakage rate in this portion ofthe seal is reduced to a minimum since it will be seen that for any partof the atmosehere to pass this seal it will have to traveL through thegasket, not cross-wise or transversely in the narrow direction butlengthwise and parallel to the drawn out portion. Hence, for practicalpurposes there is no leakage to speak of through this portion of theseal.

Thirdly, there is the cushion seal formed between the upper edge portion3G orr the glass finish and the thick portion Z3 of the gasket. This isthe portion oi the gasket which `hears the greatest load when thepackage undergoes retorting with high overriding or dilerentialpressures.

Heretofore, withother caps having thinner cushions ofv gasket materialin this region, it was not uncommon for the high overriding pressures toresult in the'gasket being completely penetrated so that the glasslinish in eect severed the cushion and reached the metal shell itself.in the gasket lll the amount of material disposed in the channel l5' issutlicient so as to prevent such penetration from occurring.

arreglos By reason of the padding and cushioning 4action provided by thethick portion 23 of the gasket, the sealed package is able to withstandsubstantial and repeated impacts and shocks received in generally axialdirection. Since the tapered, elongated portion 24 of the gasket ismaintained under compression in confined relationship between the glassfinish and the cap shell, it is able to withstand substantial impactsfrom a generally lateral direction. The net result is that a packagesealed with the closure cap 6 is more resistant to shocks and impactswithout the hermetic seal being 'oroken than caps of this typeheretofore provided. Y

The closure cap 6 described above in detail in connection with theaccompanying drawings represents the presently preferred embodiment ofmy invention. However, certain changes may 'be made in it. For example,the cap shell on the lower portion of the skirt could be provided withthread formations rather than the lugs l2 so as to he a screw cap forcooperation with exterior threads on the glass finish. The exteriordiameter of the bottom or outermost skirt portion 22 may be reducedsomewhat, and -minor variations may he made in the contour of the upper`stepped portion of the shell. Minor variations may he made inproportions.

Since the above and certain other minor changes 4may be made withoutdeparting from the spirit and scope of the invention, the foregoingdescription is intended to be interpreted as illustrative and not in alimiting sense.

What is claimed as new is:

l. In a closure cap of the -top and side seal type for use inestablishing and maintaining a hermetic seal on a glass container of thetype in which the upper edge of the rim together with a portion of theside surface thereof constitute the hermetic sealing finish, and saidcap coniprising a generally cup-shaped shell having a top panel portionwith the margin having a down-turned channel formation to register withsaid upper edge and having a stepped skirt portion with the upper innerstep thereof integrally joining the outer wall of said channel formationas a continuation thereof and providing a downwardly and outwardlytapered side portion the bottom of which directly joins an outwardlyflared shoulderportion, the improvement comprising an annular sealinggasket located generally within the corner of said shell having itsupper and inner edge located on the underside of said top panel portionadjacent the bottom of the inner side wall of said channel formationwith its lower and outer edge terminating in `a feather edge on theunder-side of said outwardly flared shoulder portion, with said gasketfilling said channel formation and having a downwardly and outwardlytapered portion which .rapidly diminishes in cross-section below saidchannel formation and follows said tapered side portion and saidoutwardly flared shoulder portion and extends to said feather edge, saiddownwardly and outwardlyr tapered portion being at least several timeslonger than the thickness of said channel filling portion; said channelfilling portion of said gasket sealingly engaging said upper edge of thesealing finish of said container when said closure cap is hermeticallysealed thereon with said tapered portion of said gasket being at leastpartially thinned out by compressed sealing engagement with said sideportion of said sealing finish, and said feather edge lyingsubstantially outwardly of said sealing finish.

2. in a closure cap of the combination top and side seal type for use inestablishing and maintaining a hermetic seal on a glass container of thetype in which the top edge of the rim together with a contiguousdownwardly tapered side surface portion having a height approximatelyequal to the width of said top edge constitute the hermetic sealingfinish, and said cap comprising a generally cupsliaped shell having atop panel portion with the margin thereof having a down-turned channelformation to register with said upper edge and having a stepped skirtportion with the upper inner step thereof integrally joining the outerwall of said channel formation as a downwardly and outwardly taperedcontinuation portion the lower end of which directly joins an outwardlyand `downwardly flared shoulder portion of said skirt which connectswith the lower outer step of the skirt which carries inwardly projectingformations for retaining the cap on a container, the improvement whichcomprises an annular sealing gasket located generally within the cornerof said shell having its lupper and inner edge located on the undersideof said top panel portion adjacent the bottom of the inner side wall ofsaid channel formation and its lower and outer edge terminating in afeather edge on the underside of said shoulder portion, said gaskethaving an upper cushion portion which fills said channel formation and adownwardly and outwardly ltapered portion which rapidly diminishes incross-section 1oelow said channel formation and follows said taperedcontinuation portion of the shell skirt and connects with said featheredge said downwardly and outwardly tapered portion being at leastseveral times longer than the thickness of said channel filling portion,the inner contour of said gasket when uncompressed being generallyarcuate from its upper inner edge to the lower end of said downwardlyand outwardly tapered portion thereof, said channel filling portieri ofsaid gasket sealingly engaging said top edge of the container rim whensaid closure cap is hermeticaliy sealed thereon with said taperedportion of said gasket being at least partially thinned out and radiallycompressed into sealing engagement with said tapered side surface of thesealing finish, and said feather edge portion being disposedsubstantially outwardly of any portion of said sealing finish, saidradial compression on said tapered portion of said gasket being providedby outward flexing of said downwardly and outwardly tapered continuationportion of said skirt.

3. The improvement called for in claim 2 wherein said gasket is formedof a cured plastisol.

4. The improvement called for in claim 2 wherein the inner contour 'ofsaid gasket when uncompressed is generally S-shaped starting at saidupper and inner edge and ending at said feather edge.

5. A sealed package comprising a glass container having a hermeticsealing finish provided in part by the top edge of the rim and in partby a contiguous downwardly tapered side surface and having protrudingcap-retaining means helow said finish and a closure cap in hermeticallysealed relationship on the top of sai-d container, said cap comprising agenerally cup-shaped shell having a top panel portion with the marginthereof having a down-turned channel formation in registry with said topedge of said sealing finish and having a stepped skirt portion with theupper inner step thereof integrally joining the outer wall of saidchannel formation as a downwardly and outwardly tapered continuationportion which telescopes over said tapered side surface of said sealingnish with the lower end thereof directly joining an outwardly anddownwardly flared shoulder portion of said skirt which in turn directlyjoins a lower outer step portion of the skirt which has inwardlyprotruding `cap-retaining means in engagement with said cap-retainingmeans on said finish, and an annular sealing gasket locate-d generallywithin the corner of said shell having its upper inner edge located onthe underside of said top panel portion adjacent the bottom of the innerside -wall of said channel formation and its lower and outer edgeterminating in a feather edge on the underside of said shoulder portion,said gasket in its compresse sealing condition being generallyladle-shaped in cross-section having an upper cushion portioncorresponding to a ladle howl and lling said :channel lfor-ination andhaving a downwardly `and outwardly tapered portion corresponding to aladle handle which follows said tapered side portion and said outwardlyflared shoulder portion of said shell skirt and extends to saidfeathered edge, said upper cushion portion sealingly engaging said topedge of sai-d finish and that section of the length of said taperedportion of the gasket which lies between said tapered side surface ofthe ysealing finish and said 1 ogn-,409

tapered side porion of said skirt being radially thinned Refeemes Ce inthe io of this paten out and compressed into saiing engagement with saidr QT tapsred side surface by hoop `tonsion provided lby outward UNTLD@LATES PATENTS L- v l f g i a e n rg 0 S51 d d0 @Hardly an@ @1 y frrdlij raw d Comm 2,453,791; Krueger Man 8, 1949 nation portion of sa1dskirt, and said Ieatner edge portion 5 3 n, 7 04S Foye Jan 16 1962 f um,L x i ,L L ybolug disposed substanumiy ou-ward1y of amJ porton of1328,65 Geddes "i APL 3 1962 said seaing finish.

1. IN A CLOSURE CAP OF THE TOP AND SIDE SEAL TYPE FOR USE INESTABLISHING AND MAINTAINING A HERMETIC SEAL ON A GLASS CONTAINER OF THETYPE IN WHICH THE UPPER EDGE OF THE RIM TOGETHER WITH A PORTION OF THESIDE SURFACE THEREOF CONSTITUTE THE HERMETIC SEALING FINISH, AND SAIDCAP COMPRISING A GENERALLY CUP-SHAPED SHELL HAVING A TOP PANEL PORTIONWITH THE MARGIN HAVING A DOWN-TURNED CHANNEL FORMATION TO REGISTER WITHSAID UPPER EDGE AND HAVING A STEPPED SKIRT PORTION WITH THE UPPER INNERSTEP THEREOF INTEGRALLY JOINING THE OUTER WALL OF SAID CHANNEL FORMATIONAS A CONTINUATION THEREOF AND PROVIDING A DOWNWARDLY AND OUTWARDLYTAPERED SIDE PORTION THE BOTTOM OF WHICH DIRECTLY JOINS AN OUTWARDLYFLARED SHOULDER PORTION, THE IMPROVEMENT COMPRISING AN ANNULAR SEALINGGASKET LOCATED GENERALLY WITHIN THE CORNER OF SAID SHELL HAVING ITSUPPER AND INNER EDGE LOCATED ON THE UNDERSIDE OF SAID TOP PANEL PORTIONADJACENT THE BOTTOM OF THE INNER SIDE WALL OF SAID CHANNEL FORMATIONWITH ITS LOWER AND OUTER EDGE TERMINATING IN A FEATHER EDGE ON THEUNDER-SIDE OF SAID OUTWARDLY FLARED SHOULDER PORTION, WITH SAID GASKETFILLING SAID CHANNEL FORMATION AND HAVING A DOWNWARDLY AND OUTWARDLYTAPERED PORTION WHICH RAPIDLY DIMINISHES IN CROSS-SECTION BELOW SAIDCHANNEL FORMATION AND FOLLOWS SAID TAPERED SIDE PORTION AND SAIDOUTWARDLY FLARED SHOULDER PORTION AND EXTENDS TO SAID FEATHER EDGE, SAIDDOWNWARDLY AND OUTWARDLY TAPERED PORTION BEING AT LEAST SEVERAL TIMESLONGER THAN THE THICKNESS OF SAID CHANNEL FILLING PORTION; SAID CHANNELFILLING PORTION OF SAID GASKET SEALINGLY ENGAGING SAID UPPER EDGE OF THESEALING FINISH OF SAID CONTAINER WHEN SAID CLOSURE CAP IS HERMETICALLYSEALED THEREON WITH SAID TAPERED PORTION OF SAID GASKET BEING AT LEASTPARTIALLY THINNED OUT BY COMPRESSED SEALING ENGAGEMENT WITH SAID SIDEPORTION OF SAID SEALING FINISH, AND SAID FEATHER EDGE LYINGSUBSTANTIALLY OUTWARDLY OF SAID SEALING FINISH.